Study On Composition And Methodology Of Extraction And Separation For Migao's Essential Oil

Migao (Cinnamomum Migao H.W.Li.) is a traditional Chinese herbal medicine,which is used to cure the stomachache, coronary heart disease and angina pectoris,used in Miao tribe of Guizhou Province of China. According to previous research, ithas been proved that the essential oil extracted from dry Migao's fruit possessesmedicine function, but which compositions of the essential oil are the activecomponents part for curing disease is unknown up to now. In order to understand andseparate the complete components, a green extraction and separation processes forMigao' essential oil were studied systematically in both experiment and theory in thisthesis. The effect of various operating parameters on supercritical fluid extraction(SFE)of the dry Migao's fruit with supercritical carbon dioxide was studied in detail, andthe optimum extractions scheme were obtained. Comparing the experimental data ofSFE with traditional stream distillation(SD) and Soxhlet's extraction(SE), it wasfound that the supercritical fluid extraction method is better than stream distillationand oxhlet's extraction in terms of quality and yield. Based on the experimental data and theoretical analyses, the kinetics ofsupercritical extraction process of Migao is controlled by external diffusion of masstransfer, the effect of internal diffusion of mass transfer could be neglected, and theimage of scanning electron microscope(SEM) of both un-extracted and extractedmaterial particle show that the most of essential oils called "free oil" are exposed onthe surface of particle, only a minority of essential oils called "tied oil" are absorbedin the broken cell. On the basis of above diffusion characteristics, the mathematicalmodel was established for describing this transfer mechanism, simulated results showgood agreements with the experimental data and was applied to predict the pilot scaleexperimental result successfully. Moreover, an empirical correlation equation and aneural network model were also used to simulate the supercritical extraction processof Migao's essential oil for modelling comparisons. The essential oil of Migao extracted by supercritical fluid extraction was separatedinto a number of fractions by molecular distillation(MD) and separated into severalfractions by traditional column chromatography. All the experimental results show thatthe molecular distillation gives a better separating efficiency than columnchromatography does. The compositions of essential oil extracted by different methods and their fractionsseparated by different methods were analyzed using the gas chromatography (GC) andthe gas chromatography-mass spectrometer (GC-MS). In the essential oil extracted bySFE and its fractions separated by MD, 98 compounds have been identified, especially,in which 52 compounds were not reported in previous literatures. The essential oil obtained either by supercritical carbon dioxide extraction or bytraditional stream distillation was proved to be the Newtonian fluid through studyingthe rheology of essential oils using rotational viscometer. The viscosities and densitiesof the essential oil were measured at different temperatures and correlated in format ofAndrade equation and temperature polynomial function respectively.